Volatile anaesthetic vaporizing apparatus



United States Patent 3,192,924 VOLATILE ANAESTHETIC VAlfiRIZING APPARATUS William Edmondson and Wilfred Jones, Keighley, England, assignors to Cyprane Limited, Keighiey, England, a company of Great Britain Filed Feb. 11, 1963, Ser. No. 257,673 Claims priority, application Great Britain, Feb. 15, 1962, 5,809/62 9 Claims. (Cl. 128-188) This invention relates to apparatus capable of mixing the vapour of a volatile anaesthetic with a gaseous fluid, such as air, oxygen, or nitrous oxide, or a combination thereof, all of which for convenience are hereinafter included in the term gas.

There are various types of vaporizing apparatus and the type with which this invention is concerned is designed to control the flow of the gas so that it can pass straight through the apparatus or a part thereof be adapted to pick up and vaporise liquid anaesthetic for a percentage of vapour to enter the gas stream. It is known for such apparatus to be capable of controlling the percentage of gas or gas-vapour accurately and it is the main object of the present invention to provide an improved apparatus of this type.

According to the present invention there is provided vaporizing apparatus for a volatile anaesthetic, including a container for liquid anaesthetic and wherein such liquid can be vaporised by the inflow of gas, a gas inlet port to and a gas-vapour outlet port from such container, a rotary plate valve normally closing such ports and located in a through chamber for gas, said valve also being positioned in relation to a pair of faces having equal gradients of a predetermined formation, the arrangement being such that rotation of the valve uncovers the gas inlet and gas-vapour outlet ports and simultaneously varies the area of the through gas passageway, thus reducing the flow of gas and increasing the percentage outflow of gas-vapour.

The improved apparatus may include a body to contain the liquid anaesthetic, an inlet port to and an outlet port from the body for the flow of gas into the body and the outflow of gas-vapour, a casing on the body housing a rotary plate valve in a chamber, said valve normally closing the body inlet and outlet ports, means for manually operating said valve, a main inlet and a main outlet in the wall of said casing for connection to a gas supply source and a patients inspiring mask respectively and for allowing the direct through flow of gas through said chamber, and a pair of faces above the valve having predetermined equal gradients, whereby turning of the valve uncovers the body inlet and outlet ports for gas to be by-passed through the body for anaesthetic vaporizing purposes and said valve moves in relation to the gradient faces to vary the direct through flow of gas and percentage outflow of gas-vapour.

The apparatus body preferably includes temperature responsive valve means to control the inflow of gas to the liquid anaesthetic, or outflow of gas-vapour.

The improved apparatus also preferably is of the socalled unspillable type including an internal flow and liquid containing arrangement that ensures correct control of the percentage of the gas-vapour irrespective of the position of the apparatus.

The improved construction may be such that the operating means for the control valve is movable in relation to graduations and the gradient of each of the aforesaid faces is complementary to the graduation spacing. The valve may have ribs to move relative the gradient faces for gas control purposes.

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The invention will now be more particularly described with referenceto the accompanying drawings, in which:

FIG. 1 is a part sectional elevation of the improved apparatus; and

' FIG. 2 is a plan of FIG. 1 from above.

In the illustrated embodiment of this invention the body part 1 of the apparatus may be substantially similar to that disclosed in our prior US. Patent No. 2,915,061, dated January 1, 1959. The body illustrated in FIG. 1 may be modified in its interior to suit requirements, and, as shown, there is only a central vaporizing chamber with a second chamber 10a surrounding it with an annular division wall 10b open at the top. and which may or may not be perforated in its upper region. This division wall may serve as carrier means for absorbent wick means used to cause liquid to be raised by capillary action to facilitate vaporization by contact with gas which enters the body 1, as shown in the aforementioned US. patent. The body is furnished with an external funnellike filler part to which is furnished with a plug closure 1b. The arrangement is such that liquid anaesthetic can be poured into the part 1b to a level C in line with the lip 1c of the part 10. This arrangement prevents overtilling of the body. The temperature sensitive element 2 in this construction is adapted to control a valve 3 which controls an inlet, such as port 4, for vaporizing gas.

The top of the body 1 is closed by a sealing plate 5 which is secured to a superposed valve casing 6 and in this plate is provided an inlet port 7 and an outlet port 8 arranged diametrically opposite one another.' The inlet port is in communication with an inlet chamber 9 lying within the body and such chamber has the port 4 for the inlet of gas to the vaporizing chambers 10', 10a (or chamber) in the body. Gas-vapour passes through the port 11 into the outlet chamber 12 which is in communication with the outlet 8. With this construction the inlet of gas is controlled automatically to remain constant to a given setting irrespective of any change in temperature. Alternatively, the port 11 may be controlled by the element 2 and valve 3 as indicated.

Gas-vapour passes from the body 1 through the aforesaid outlet port 8 in the top sealing plate 5 into the valve casing 5. The said casing is provided with a main inlet 14 and an opposite main outlet 15 which are secured to the wall of the casing, they may be integral therewith, and such casing is furnished with a cap 16. The said inlet and outlet, which are sleeve-like and projecting horizontally from the casing, are adapted to receive connections in known manner respectively from a gas supply source and to a patients inspiring mask.

Within the valve casing 6 is provided a pendant bearing member 17 through which is passed a spindle 18 for a plate valve 19 which normally lies on the upper face of the aforesaid ported body sealing plate v5. The valve spindle 18 is furnished at its upper end with a horizontal lever 2t which projects through a gap 21 'in the casing cap 16 with gripping means 22 at its extremity so that as the lever is moved about the axis of thespindle the latter will rotate the plate valve 19 on the ported plate 5." Normally the plate valve in the oif-position covers the two ports 7 and 8 and movement in an anti-clockwise direction according to FIG. 2 uncovers such ports until they are fully open. The action of the valve in relation to these ports is merely to open or close them. It will be understood that only a small rotation of the spindle 18 will only partly uncover the ports but this is incidental in regard to the true working of the invention. Move- Patented July 6, 1965 i ment of the plate valve 19 from minimum to maximum is assisted by the provision of graduations 23 and marking 2.4 on the upper face of the cap 16 and gripping means 22 respectively.

The aforesaid cap 16, or valve casing 6, is furnished with pendant parts 25 provided with a pair of underneath faces 2a; which are substantially quadrant shaped (in plan) and have equal gradients. The gradients travel in the same rotary direction from a high point A, where there is the widest gap between the gradient and the valve 19 to a lower point B, where there is the narrowest gap. Such gradients can be calculated to suit the spacing of the aforesaid graduations. In other words, the gradient faces 26 need not be regular inclines but may be variable to facilitate the graduating of the cap. Such gradient faces 26 lie immediately above diametrically opposite upstanding ribs 27 on the plate valve 19 so that with the valve in its normal closed position the ribs 27 will lie immediately beyond the ends A of the gradient faces Where there would be the greatest gap 28 between the ribs and such faces. With the valve in this position there can be a maximum flow of gas through the casing 6 from the main inlet 14 to the main outlet 15. As the valve 19 is rotated to uncover the body inlet and outlet ports 7, 8 the valve ribs 27 will approach and then be moving in relation to the gradients 25 and thus reducing the flow of gas through the casing 6 and a percentage is allowed to flow down into the body 1. The arrangement may be such that with the valve 19 (and the body inlet and outlet ports 7, 8) in the fully open position the through flow of gas may be cut off entirely, or alternatively as shown a required minimum gap 29 left and thus the highest percentage of gas-vapour flow provided. The ribs 27 are shown slightly off-set in opposite directions.

With the above arrangement the depth of the ribbed plate valve 19 and the position of the gradient faces 26 in relation to the top of the ribs of the plate valve may be calculated and machined accurately to provide accurate percentages of gas 'or gas-vapour according to the graduations furnished on the casing top.

An important feature of the construction is that the vaporizing apparatus is non-spillable. With the vaporizer upright, and charged with liquid anaesthetic, the liquid level will be at C, if the device is inverted the level will be at D and on its side the level will be at E. In any of these positions the inlet 4 and outlet 11 are both above the liquid and the latter cannot pour into the valve casing. The main point of this is that these Vaporizers may be carried around charged with the control lever not in the off position. If Pluothane does get into the top valve chamber and it is then used, the patient would receive a strong dose of Fluothane even if the lever were in the off position.

The aforesaid apparatus is eminently suitable for use with liquid anaesthetic, such as Fluothane (Registered Trade Mark) and due to the nature of such a liquid the face of the plate valve 19 may comprise a material such as Fluon (Registered Trade Mark). The plate valve 19 may be a disc but it is preferred to make it in the form of a central disc with laterally extending flat arms as shown. If desired the distance between the gradient faces and valve ribs may be adjustable for setting purposes.

What we claim is:

1. Vaporizing apparatus for a volatile anaesthetic including,

a body forming a container for liquid anaesthetic and wherein such liquid can be vaporized by the inflow of gas;

a through chamber for gas located above said container;

a main inlet to and a main inlet outlet from said eases lls lit

chamber for the through flow of gas; a gas inlet port from said chamber to said container; a gas-anesthetic vapor outlet port from said container to said chamber;

a rotary plate valve located in said chamber and normally closing said ports;

barrier means in said chamber forming a pair of faces having equal gradients of a predetermined formation and lying immediately over said valve;

said valve having surfaces to move in one plane adjacent said faces to combine therewith in forming means for controlling a flow area therebetween for gas flowing through the chamber between its main inlet and main outlet;

manual operating means for causing rotation of the valve initially and to uncover said gas inlet port and gas-vapour outlet port and upon further rotation to vary the size of said flow area of the through gas chamber by movement of the valve surfaces in relation to said gradient faces thereby reducing the flow of gas through said chamber for diluting mixture with the outgoing anaesthetic vapour.

2.. vaporizing apparatus according to claim 1, incor- V porating temperature responsive valve means for controlling the inflow of gas to the liquid anaesthetic in the apparatus body.

3. vaporizing apparatus according to claim 1, incorporating temperature responsive valve means for con trolling the outflow of gas-vapour from the apparatus body.

t. Vaporizing apparatus according to claim 1, wherein the gradient faces extend from the wall of the valve casing to a central area common to both faces, a central pendant bearing forming said common area, a spindle in said bearing for operating the plate valve, such valve eing mounted for part rotation substantially only between the extremities of such gradient faces, said central bearing forming barrier means for causing gas to flow from the main inlet to the main outlet of the valve casmg and to be divided and flow solely over the said gradient faces and thus be controllable by the rotation of the valve in relation to, and between the extremities of, such faces.

1 5. vaporizing apparatus according to claim 1, wherein the operating means for the control plate valve is movable in relation to graduations and the gradient of each of the aforesaid faces is complementary to the graduatron spacing.

6. vaporizing apparatus according to claim 1, wherein the rotary plate valve is furnished with upstanding ribs to move relative the gradient faces for gas control purposes.

7. vaporizing apparatus according to claim 1, wherein the gradient faces are substantially quadrant shaped in plan.

3. vaporizing apparatus according to claim 1, including a valve casing forming said gas through chamber and a housing for said rotary valve, said casing being seated down onto said body, said body including gas vaporizing chambers disposed one within the other in free communication, said gas inlet port'and vapor outlet port extending through the top of said body, said ports being connected respectively with inlet and outlet chambers within the body, ports between such chambers and the vaporizing chambers for the inlet of gas and outlet of gas-vapour respectively, one of such latter ports being controlled by a valve carried by a temperature sensitive element.

9, vaporizing apparatus according to claim 3, wherein the inlet and outlet ports within the body are so positioned that liquid will not pass into the plate valve chamber whether the apparatus is upright, inverted or on its (References on following page) 5 V 6 References Cited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 1,119,998 4/56 France. 704 54 7 02 ffi 137 311 X 814,427 6/ 59 Great 1:22;??? 21 1 Eg 5 HARRY B. THORNTON, Primary Examiner.

2,941,528 6/60 Fabian et al. 2617-420 

1. VAPORIZING APPARATUS FOR A VOLATILE ANAESTHETIC INCLUDING, A BODY FORMING A CONTAINER FOR LIQUID ANAESTHETIC AND WHEREIN SUCH LIQUID CAN BE VAPORIZED BY THE INFLOW OF GAS; A THROUGH CHAMBER FOR GAS LOCATED ABOVE SAID CONTAINER; A MAIN INLET TO AND A MAIN INLET OUTLET FROM SAID CHAMBER FOR THE THROUGH FLOW OF GAS; A GAS INLET PORT FROM SAID CHAMBER TO SAID CONTAINER; A GAS-ANESTHETIC VAPOR OUTLET PORT FROM SAID CONNTAINER TO SAID CHAMBER; A ROTARY PLATE VALVE LOCATED IN SAID CHAMBER AND NORMALLY CLOSING SAID PORTS; BARRIER MEANS IN SAID CHAMBER FORMING A PAIR OF FACES HAVING EQUAL GRADIENTS OF A PREDETERMINED FORMATION AND LYING IMMEDIATELY OVER SAID VALVE; SAID VALVE HAVING SURFACES TO MOVE IN ONE PLATE ADJACENT SAID FACES TO COMBINE THEREWITH IN FORMING MEANS FOR CONTROLLING A FLOW AREA THEREBETWEEN FOR GAS FLOWING THROUGH THE CHAMBER BETWEEN ITS MAIN INLET AND MAIN OUTLET; MANUAL OPERATING MEANS FOR CAUSING ROTATION OF THE VALVE INITIALLY AND TO UNCOVER SAID GAS INLET PORT AND GAS-VAPOR OUTLET PORT AND UPON FURTHER ROTATION TO VARY THE SIZE OF SAID FLOW AREA OF THE THROUGH GAS CHAMBER BY MOVEMENT OF THE VALVE SURFACES IN RELATION TO SAID GRADIENT FACES THEREBY REDUCING THE FLOW OF GAS THROUGH SAID CHAMBER FOR DILUTING MIXTURE WITH THE OUTGOING ANAESTHETIC VAPOR. 